In compressing gas refrigerant, the pressure of the refrigerant rises and the temperature thereof also rises. In a refrigeration cycle, the pressure is increased to a target high pressure. To eliminate or reduce a likelihood that the temperature will automatically rise too high, a method of injecting liquid refrigerant and using heat of evaporation of the refrigerant to reduce the temperature is used.
A scroll compressor includes a fixed scroll including a base plate and a scroll lap and an orbiting scroll including a base plate and a scroll lap. The orbiting scroll is allowed to orbit. The scroll laps of the fixed scroll and the orbiting scroll engage with each other, thus defining compression chambers. The compression chambers include an intermediate chamber for reducing the volume of low pressure gas taken such that the pressure of the gas is increased to a target high pressure before the gas is discharged.
Typically, the intermediate chamber is at an intermediate pressure between the low pressure of the taken refrigerant and the target high pressure. Low temperature, high pressure liquid refrigerant is injected into the intermediate chamber through an injection passage, thus reducing the temperature of the high pressure gas to be discharged from the compressor. Typically, the above-described injection passage extends through the base plate of the fixed scroll from a rear surface of the base plate toward the scroll lap of the fixed scroll.
A known scroll compressor includes a fixed scroll, an orbiting scroll, and a seal for sealing a clearance between a lower surface (lap bottom) of a base plate of the fixed scroll and the tip of a scroll lap of the orbiting scroll (refer to Patent Literature 1, for example).